1. Field of The Invention
The invention relates to an epoxy resin composition. More particularly, the invention relates to epoxy curing agent. Most particularly the invention relates to epoxy curing agents comprising the Mannich condensation product of a phenol, formaldehyde and a polyoxyethylenediamine.
2. Description Of The Related Art
Epoxy resins constitute a broad class of polymeric materials having a wide range of physical properties. The resins are characterized by epoxide groups which are cured by reaction with certain catalysts or curing agents to provide cured epoxy resin compositions with certain desirable properties.
The most common epoxy resins are a condensation product of epichlorohydrin and bisphenol A. Epoxy resins are cured with any of the conventional curing agents such as polyamines, polycarboxylic acids, anhydrides and Lewis acids.
Mannich condensation is a well-known reaction wherein a phenolic compound is reacted with formaldehyde and a primary or secondary amine to provide a substituted aminomethyl derivative of the phenolic starting material.
U.S. Pat. No. 3,236,895 to J. M. Lee and J. C. Winfrey teaches the preparation of polyoxyalkylenepolyamines. These amines are used for curing epoxy resin compositions.
U.S. Pat. No. 3,734,965 to W. Becker et al. teaches phenolic resins having a polyoxypropyleneamine substituent. These compounds are used as curing agents for epoxy resins.
U.S. Pat. No. 3,847,726 to W. Becker et al., teaches vibration-damping sheet laminates. The laminates comprise epoxy resins which are cured with a polyether amine which is a Mannich condensation product of a phenol, an aldehyde and a polyoxypropylene amine.
U.S. Pat. No. 4,006,089 to S. Chibnik teaches polyoxyethylene polyamine Mannich base products used in fuels and lubricants.